IG window units are known in the art, including, for example, those described in U.S. Pat. Nos. 6,632,491 and 6,946,171, which are hereby incorporated herein by reference. An IG window unit generally includes at least first and second substrates spaced apart from one another by at least one spacer and/or seal. The gap or space between the spaced apart substrates may be filled with a gas (e.g., argon) and/or may be evacuated to a pressure less than atmospheric pressure in different instances.
Many conventional IG window units include a solar management coating (e.g., a multi-layer coating for reflecting at least some infrared radiation) on an interior surface of one of the substrates. Example solar management or control coatings are described in U.S. Pat. Nos. 6,632,491, 6,926,967, 6,908,679, 6,749,941, 6,782,718, 6,576,349, and 7,090,921, the disclosures of which are hereby incorporated herein by reference. Such IG units may facilitate the blocking of significant amounts of infrared (IR) radiation, which may reduce the amount of IR radiation reaching the interior of the building (e.g., apartment, house, office building, etc.), via the solar control/management coating(s). Some conventional IG window units also include a coating for blocking ultraviolet (UV) radiation on the interior surface of one of the substrates.
Certain conventional IG window units lack a hydrophilic coating (e.g., an anti-fog coating) on an exterior/interior surface thereof. A hydrophilic coating may prevent the agglomeration of water drops into gobular shapes. That is, a hydrophilic coating is characterized by a low contact angle θ and may reduce bead-like condensation on the surfaces of the substrates in an IG window unit and, thus, may reduce the formation of tiny droplets of liquid. This film-wise (as opposed to droplet-wise) condensation may improve visibility through the IG window unit.
Silicon oxide coatings have been deposited on glass via sputter deposition. But once an IG window unit is assembled, it may be difficult to use sputter deposition to place such a layer on a glass surface because it would be difficult if not impossible to run an assembled IG unit through a sputter-coating apparatus.
There exists a need in the art to provide a method of assembling an IG (insulating glass) window unit, having a hydrophilic coating such as a coating of or including silicon oxide deposited on a surface of the unit via chemical vapor deposition.